Fuel injection nozzle



Oct. 1, 1963 R. L. ALLEN 3,105,640

FUEL INJECTION NOZZLE Filed Dec. 19, 1957 HQ 3 ROBERT L. ALLEN ATTORN E! United States Patent 3,105,646 FUEL INJECTIQN NGZZLE Robert L. Allen, Atlanta, Ga, assignor to Georgia Tech Research Institute, Atlanta, Ga, a corporation of Georgia Filed Dec. 19, 1957, Ser. No. 703,876 3 Claims. (61. 23-453) This invention relates to a spray nozzle, and is particularly concerned with the provision of a nozzle for the uniform spraying, difiusing or atomizing of liquids delivcred over a wide range of flow rates.

While the art relating to devices for spraying, atomizing and diffusing liquids is ancient and highly developed, there are, nevertheless, many important problems which have not been fully solved by structures, commercially available or known to persons skilled in the art. Among such problems is that of providing a uniform spray pattern and high degree of atomization over a wide range of flow rates. Another problem is to provide a minimum length restrictive path of flow and hence a spray nozzle having a rapid, substantially instantaneous pressure drop upon discharge, whereby diliusion will be rapid and complete. A further problem which has not been solved to the extent of complete satisfaction is that of minimizing efficiency losses due to drag friction and the adherence of fluid to the nozzle element. The achievement of an effective and eflicient nozzle which will be rugged and durable while complying with the demands of economic manufacture is also an ever present consideration in the minds of designers of spray nozzles.

In that form of the present invention, 'here shown by way of illustration, applicant has advanced in the direction of a solution to these and other problems of spray nozzle design and manufacture by a structure which may be generally defined as including a hollow body providing an outlet orifice cooperating with a free floating diffusion element, preferably urged to seating position by resilient means. This diffusion element presents a frusto-conical surface facing the direction of fluid flow, and terminating in a sharp circular edge, characterized by a radius slightly exceeding but closely approaching that of the radius of the outlet orifice with which it is associated to minimize the length of the path of travel of fluid in a restricted zone. Hence, drag, skin friction and turbulence are avoided as well as the formation of a selfsperpetuating consolidated stream. Since pressure drop is almost instantaneous as the fluid passes from the nozzle, diflusi-on inherently follows almost immediately.

In the present form of the invention, the body is formed with a uniformly cylindrical outlet bore, insuring free direct passage of liquid, terminating in a circular flow orifice forming a companion seat for the diffusion element. The outer wall of the body adjoining the seat is formed as a frusto-conical surface meeting the orifice periphery at a sharp; acute angle, the apex of which defines the seat as a sharp circular edge. Since the acute angle between inner and outer body walls at the orifice provides a sharp edge confronting the smooth tip edge surface of the inwardly facing conical surface of the diffusion head, a sharp circular line contact between the element and its seat is achieved. In carrying out this construction, a simple cylindrical body is utilized which is readily formed from bar stock. Internal threads provide for the adjustable support of the diffusion element, as well as the mounting of a closure plug and supply line connection. Thus the nozzle is rugged, durable and well designed to meet the demands of economic manufacture.

From the foregoing it will be seen that it is among the more general objects of the present invention to provide a novel and improved spraying, sprinkling and .difiusing ice 2. nozzle designed to provide uniform, eifective and eflicient sprinkling, spraying and diffusion of liquids.

Another object of the invention is to provide a nozzle of the type referred to so constructed and arranged as to minimize turbulence, firictional drag, retardation of fluid flow and the clinging of fluid t-o nozzle components.

It is also an important object of the invention to provide a nozzle in the operation of which a rapid and substantially instantaneous pressure drop is insured as the fluid emerges therefrom.

A further object of the invention includes that of providing a device of the character described which is simple in construction and operation, requiring minimum maintenance and adjustment, and one which may be economically manufactured without sacrifice of strength, durability, or effective and efilcient operation over a long period of time.

Numerous other objects, features and advantages of the present invention will be apparent from consideration of the following specification taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a side elevation of one form of the present invention.

FIG. 2 is a vertical cross sectional view through the nozzle depicted in FIG. 1.

FIG. 3 is an enlarged detail view illustrating the relation of the diffusion element and its seat.

FIG. 4 is a detail perspective view of the diffusion element spring supporting ring.

Referring more particularly to the drawings, it will be seen that the body 10 may be readily and inexpensively formed from a generally cylindrical blank. For mounting the nozzle in operative position with respect to associated equipment, the lowerend of the upper cylindrical portion of the outer surface of the body 10 may be formed with external threads indicated at 11. Internally, the body is formed with a central longitudinally extending axial bore forming a central cavity 12 having internal threads 13. The lower end of the body below the threads 13 is formed with an axial reduced fluid outlet bore 14 which is open to the cavity 12, by merging therewith through the intermediary of a short internal frustoconical Wall 15. The opposite outer end of the bore 14 terminates in an orifice form'ed'as a sharp knife-like circular seat 17 at the apex between the inner perpendicular walls ofthe bore 14 and the outer downwardly and inwardly tapering frusto-conical wall 16 of the body below the threads 11.

As here shown, the wall of the bore 14 is concentric with the wall 15 of-the cylindrical cavity 12, and thus axial with respect to the body. The inward and downward taper of the-frusto-conical outer surface 16 of the body meets the wall of the base at an acute angle to form the sharp smooth circular seat 17. While the angularity between the wall of the bore 14 and the outer frustoconical surface 16 may not be critical, it is nevertheless desirable that this angle be such as to insure a circular line contact between the seat 17 and the diffusion head. At the opposite end of the body It), the cavity 12 is capped by a threaded plug 18, having a central fluid supply duct 19 to which is applied the fluid supply tube 20.

Mounted within the cavity and adjustably engaging a selected turn of the threads 13 below the plug 18, there is located the annulus 21 of a spring supporting ring. A V-shaped cross-bar 22, formed integrally with and depending from the annulus 21, receives the upper terminal end 23 of a light coil spring 24. Axial adjustment of the ring within the cavity may be conveniently obtained by rotation of the annulus 21 for thread-like adjustment in the body 10. The lower end 25 of the spring 24 engages the ring 26 of the shank 27 of the diffusion element to V freely suspend the element within the body. At the lower end of the shank 27 a diffusion head 28 is formed integrally with the shank 27.

The head 28'comprises a disc-like member having an upper frusto-conical fluid contact surface 29 facing the direction of fluid 'flow from the bore 14. The head 28 is of minimum radius capable of providing sealing contact with the sharp circular seat 17. The under or outer side of the head 28 is here shown as a flat circular surface 30 disposed in a plane normal to the axis of the head and joining the outer periphery of the surface 29 at an acute angle to provide a short, thin, sharp and acutely angled lip 31 of minimum overhang. As more clearly illustrated in FIG. 3, the sharp lip 31 when seated, will contact the sharp seat 17 to provide a thin circular line contact. While, as indicated with respect to angularity forming the seat 17, the angle between the surfaces 29 and 30 may not be critical; it is, however, preferable that this angle be acute to provide a sharp edge for the lip to insure a quick and complete discharge of fluid, eliminating the danger of fluid drag or adherence and insuring rapid decrease of fluid pressure.

It will be noted that the substantially equal diameter of the head 28 with respect to the diameter of the seat 17 at the end of the fluid outlet passage 14 provides a minimum marginal lip 31 extending outwardly and downwardly from the seat 17. The frusto-conical surface including the lip will insure a radial spread of fluid discharged and the desired degree of atomization and diffusion. It will further be noted that since the diffusion element is retained in position merely by the relatively light spring 24 which is fully flexible, both laterally as well as longitudinally, the element is free floating and may move rapidly and fully from its seat 17 to be unguided and floatingly suspended by the spring. It will also be noted that the conical configuration of the surface will insure proper seating of the element against the seat, such conical formation providing a guiding action for the seating of the element under spring tension when fluid pressure is terminated.

From the foregoing, it will be seen that the present nozzle structure may be characterized as including a discharge orifice bounded by a sharp smooth circular seat from which the fluid may be rapidly discharged with minimum drag friction and without the retention of moisture or liquid droplets. This sharp terminus, externally bounded by the reversely inclined walls 16, gives a substantially instantaneous pressure drop insuring rapid diffusion. The conical diifusion head with its minimum overhang of peripheral edge, also formed at an acute angle, similarly precludes adhesion and insures rapid atomization. Such minimum overhang also diminishes the length of restrictive passage of fluid between head and seat, effectively maintaining friction at a minimum.

In considering the present invention, it will ofvcourse be understood that numerous changes, modifications and the full use of equivalents may be resorted to without departing from the spirit or scope of the invention as defined in the appended claims.

I claim:

1. A spray nozzle including a generally cylindrical body defining a threaded bore, a fluid cavity in axial alignment with said bore and an axial cylindrical outer bore communicating therewith and forming a discharge orifice, the outer wall of said body being tapered to said orifice at an acute angle to provide a sharply swept back circular seat at said discharge orifice, a diffusion head, resilient means suspending said head from within said body for free universal movement with respect thereto, said diifusion head having a frusto-conical inner surface from the edge to adjacent the center, the diameter of said surface being slightly greater than the diameter of said orifice, the opposite outer surface of said element presenting a flat face having a radially outermost periph eral sharp edge portion lying in a fiat plane normal to the axis of said inner surface, said suspending means providing yieldable contact of said inner surface with said seat, and being threadedly adjustable in the threads of said threaded bore.

2. A spray nozzle including a generally cylindrical body defining a threaded bore, a fluid cavity in axial free universal movement with respect thereto, said diifw.

sion head having a frusto -conical inner surface from the edge to adjacent the center, the diameter of said surface being slightly greater than the diameter of said orifice, said element having an outer surface with a radially outermost peripheral sharp edge portion joining the outer periphery of said inner surface and presenting a fiat face lying in a flat plane normal to the axis of said inner surface, said suspending means providing yieldable contact of said inner surface with said seat, and being threadedly adjustable in the threads of said threaded bore, said suspending means including a wire annulus adjustably engagea-ble in the threads of said threaded bore.

, 3. A fluid spray nozzle including a generally cylin. dric-al body defining a through axial fluid passage, said passage including an upper threaded bore, a central cavity communicating with said bore and a lower cylindrical outlet bore communicating with said cavity and forming a fluid outlet orifice, fluid inlet means secured in said threaded bore, a wire annulus threadedly adjustable in.

said threaded bore, a spring suspended from said annulus, a diffusion element suspended from' said spring, the lower outer wall of said body being tapered inwardly to said outlet bore at an acute angle to define a sharply swept back circular seat at said orifice, said diifusion element including a head having a conical inner surface of slightly greater diameter than the diameter of said orifice to rest upon said seat, said element also having a flat outer surfacewith a radially outermost peripheral sharp edge portion joining the outer periphery of said inner surface and lying in a flat plane substantially normal to the axis of' said conical inner surface and forming at its junction with the edge of said inner surface a sharp peripheral edge on said diifusion element.

References Cited in the file of this patent UNITED STATES PATENTS Germany May 20, 1954 Ohlsson Nov. 28, 1916 

1. A SPRAY NOZZLE INCLUDING A GENERALLY CYLINDRICAL BODY DEFINING A THEREADED BORE, A FLUID CAVITY IN AXIAL ALIGNMENT WITH SAID BORE AND AN AXIAL CYLINDRICAL OUTER BORE COMMUNICATING THEREWITH AND FORMING A DISCHARGE ORIFICE, THE OUTER WALL OF SAID BODY BEING TAPERED TO SAID ORIFICE AT AN ACUTE ANGLE TO PROVIDE A SHARPLY SWEPT BACK CIRCULAR SEAT AT SAID DISCHARGE ORIFICE, A DIFFUSION HEAD, RESILIENT MEANS SUSPENDING SAID HEAD FROM WITHIN SAID BODY FOR FREE UNIVERSAL MOVEMENT WITH RESPECT THERETO, SAID DIFFUSION HEAD HAVING A FRUSTO-CONICAL INNER SURFACE FROM THE EDGE TO ADJACENT THE CENTER, THE DIAMETER OF SAID SURFACE BEING SLIGHTLY GREATER THAN THE DIAMETER OF SAID ORFICE, THE OPPOSITE OUTER SURFACE OF SAID ELEMENT PRESENTING A FLAT FACE HAVING A RADIALLY COUERMOST PERIPHERAL SHARP EDGE PORTION LYING IN A FLAT PLANE NORMAL TO THE AXIS OF SAID INNER SURFACE, SAID SUSPENDING MEANS PROVIDING YIELDABLE CONTACT OF SAID INNER SURFACE WITH SAID SEAT, AND BEING THREADEDLY ADJUSTABLE IN THE THREADS OF SAID THREADED BORE. 